Small powered devices (such as sensors, routers, gateway, etc.) are deployed on the open plantation for profiling the environment conditions, using wireless sensor network (WSN) which is usually off the power supply grid. Normally, these small devices are powered by batteries. However, as batteries have limited capacity and lifetime, it is in need to replace or recharge batteries regularly. As in WSN the numbers of devices are in thousands, replacing batteries is simply not practical. Thus, for realistic deployment of WSN it is necessary to make the entire WSN component is capable of energy harvesting from its ambient sources.
One of the sources of harvesting energy is from mechanical induced vibration that converts the mechanical energy to electrical energy. This vibrating energy is captured from mechanical movement of different elements such as piezoelectric, electrostatic or electromagnetic. Usually, an apparatus that can harvest energy from mechanical movement is attached with a vibrating body or machine (such as engine, running vehicle, rotating machinery etc). However one of the bottlenecks of vibrating energy harvesting is the availability of vibrating sources especially in the distant plantation. Therefore, a novel design of apparatus required to produce huge vibration from ambient low vibrating sources.
With rapid development in remote and wireless sensor networks, batteries are becoming the limiting factor in the lifetime of the device. Besides, for self-contained sensors and processing circuits, renewable on-board power supply is required, to become truly autonomous. One way to recharge battery in the system is through energy harvesting and a common method to harvest energy is from vibrations, a procedure to convert ambient vibration energy into electricity through the use of piezoelectric, electrostatic or electromagnetic materials.
Conventionally to induce mechanical vibration, apparatus capable of energy harvesting from vibration are attached with highly vibrating sources. But, in distant plantation, the availability of high vibrating body is completely uncertain and most of the time impossible. Therefore, an apparatus is required that amplify very small vibration available from the ambient. Besides, if the apparatus is capable of producing any auxiliary vibration the system will easily reach its resonance frequency from a very small amount of external vibration.